AVS 53rd International Symposium
    Electronic Materials and Processing Thursday Sessions
       Session EM-ThP

Paper EM-ThP43
Scanning Probe Microscopy Study of Atomic Layer Deposited Hafnium Based High-k Dielectric Films

Thursday, November 16, 2006, 5:30 pm, Room 3rd Floor Lobby

Session: Electronic Materials and Processing Poster Session
Presenter: X.-D. Wang, Freescale Semiconductor, Inc.
Authors: X.-D. Wang, Freescale Semiconductor, Inc.
D.H. Triyoso, Freescale Semiconductor, Inc.
R.I. Hegde, Freescale Semiconductor, Inc.
D. Roan, Freescale Semiconductor, Inc.
R. Gregory, Freescale Semiconductor, Inc.
Correspondent: Click to Email
Here we report on surface topography and tunneling current characteristics of atomic layer deposited hafnium based dielectric (HfO@sub 2@, Hf@sub x@Zr@sub 1-x@O@sub 2@ and Hf@sub x@Ti@sub y@O@sub z@) films with different processing conditions. The process conditions explored here are: dielectric deposition temperature, post deposition anneal, with and without capping layers for the dielectric during annealing. Atomic force microscopy (AFM) was used to characterize the surface morphology. Conducting AFM (C-AFM) provided the unique capability to characterize the film uniformity by measuring the spatial distribution of the tunneling current through the film. X-ray diffraction (XRD), transmission electron microscopy (TEM) and electrical measurements were also used for the understanding of the film properties. With optimized Ti or Zr ratios, the roughness of the dielectric films is significantly improved and resulted in smaller and more uniform grain size distribution. The addition of Ti or Zr resulted in improved uniformity of tunneling current distribution. However, without a cap layer, significant re-crystallization and roughing were still observed upon 1000°C annealing. This resulted in significant leakage at grain boundaries as revealed by C-AFM images. Adding a metal capping layer prior to annealing greatly improved the stability of the films with only minor increase in surface roughness compared to as-deposited films. Films capped with metal during annealing showed dramatically improved leakage characteristics by eliminating most of the apparent grain boundaries and by improvement of overall film roughness. With the optimized Ti or Zr ratio and metal cap during annealing, better electrical characteristics were achieved based on C-V measurements.